Chromatography apparatus



March 15, 1966 P. M. HAYES 3,

CHROMATOGRAPHY APPARATUS Original Filed May 10, 1962 s Sheets-Sheet 1 F I 6 I INVENTOR. P404 M HAM-=5 W, PM XVVW March 15, 1966 P. M. HAYES 3,240,340

CHROMATOGRAPHY APPARATUS Original Filed May 10, 1962 3 Sheets-Sheet 2 wzwdam March 15, 1966 P. M. HAYES CHROMATOGRAPHY APPARATUS Original Filed May 10, 1962 3 Sheets-Sheet 3 INVENTOR. p404 M finyzs this point.

United States Patent 3,240,340 CHROMATOGRAPHY APPARATUS Paul M. Hayes, 3511 Walnut Laue, Lafayette, Calif. Continuation of application Ser. No. 193,700, May 10, 1962. This application June 25, 1965, Ser. No. 471,499

7 Claims. (Cl. 210-198) This is a continuation of my prior copending patent application Serial Nov 193,700, filed in the US. Patent Ofiice on May 10, 1962, and now abandoned.

The present invention relates to improved chromatographic processing equipment, and more specifically, to a cabinet adapted for carrying out chromatography.

Chemical analysis of materials by chromatography provides for the determination of constituents in extremely small samples. The process is carried out by placing a minute sample of a mixture of unknown constituents at a point on a piece of filter paper or the like, and washing a predetermined solvent over the paper past Inasmuch as the,solubilities of the various constituents of the mixture are different, the several constitutents will be carried to and deposited at their different positions along the filter paper in the direction of flow of solvent. After drying of the paper so treated, analysis may be completed by determining the identity of separate substances at different points along the paper. It is also possible in carrying out chromatography analysis to also repeat the solvent washing in a direction 90 degrees displaced from the original direction of solvent flow.

Further as regards chromatography processing, it is common to employ a filter paper for initial placement of the unknown mixture thereon, and to move the solvent through the paper at a low rate of solvent travel. Commonly, the washing of the mixture of unknown constituents with the solvent is accomplished by movement of the solvent through the paper by capillary action, or the like.

The chromatography process has numerous drawbacks involved in the application thereof, including certain undesirable properties of the solvents normally employed. In the first place, the solvents are oftentimes quite odoriferous, and in addition, prolonged or extensive inhalation of the vapors of these solvents is oftentimes severely injurious to the health of the operator. Commonly, chromatography is carried out in a separate analysis room separated from other parts of chemical laboratories, at least in part because of the undesirable nature of the solvents employed therein. It is conventional to utilize open containers for the solvents employed, and to mount chromatography paper above the container and extending down into the solvent. After a predetermined period of solvent movement through the paper to thereby separate constituents of the chemical unknown applied to the paper in accordance with the individual rate of dis solution thereof, these papers are then carefully removed and dried. This drying process is normally carried out with the conventional exhaust fans utilized in chemical laboratories, and special precautions must be taken to prevent undue motion of the filter paper during drying,

and particularly to prevent any touching of separate filter papers, inasmuch as this would destroy the experimental analysis. It will be appreciated that this conventional method of chromatography exposes the operator to the fumes and vapors of the solvent. Inasmuch as chromatography processing normally requires a considerable period of time, anywhere from a few hours to more than twenty-four hours, it is seen that the odoriferous and oftentimes harmful fumes of solvents employed therein must be borne by workers over an extended period.

The present invention provides a chromatography cabinet wherein both solvent washing and drying is accomplished in an entirely enclosed unit. The operator is thus spared from even temporarily inhaling the fumes of the solvent utilized in the chromatography processing. Furthermore, the improved cabinet of the present invention prevents undue agitation of the air about filter papers employed in chromatography processing, while at the same time providing for a rapid drying of these papers. As above noted, this prevention of undue air agitation in the vicinity of chromatography papers after solvent wash ing is extremely important in order not to destroy the results of the analysis.

The present invention is illustrated in the accompanying drawings, wherein:

FIGURE 1 is a perspective view of the exterior of the chromatography cabinet of the present invention;

FIGURE 2 is a plan view of the chromatography cabinet;

FIGURE 3 is a partial sectional view taken in a central vertical plane through the cabinet and illustrating the top portion thereof; and

FIGURE 4 is a sectional view taken in the plane 4-4 of FIGURE 3 and illustrating a chromatography tray employed in the cabinet hereof.

The present invention, in brief, comprises an enclosure for containing chromatography paper during solvent flow and drying of the chromatographic sheets, hereinafter termed paper. This enclosure or cabinet has the interior thereof formed of a solvent-resistant material and is provided with a movable closure, providing access to the cabinet interior and sealing the cabinet during chromatography processing. Air inlet and outlet passages communicate with the cabinet interior and a remotely controlled plate, or the like, seals these passages from the interior of the cabinet during solvent flow. Particular provision is made for controlling air flow through the cabinet in order to preclude movement of the paper by air currents and an exhaust means draws air through the cabinet for drying so that no positive pressure can exist in the cabinet to leak solvent fumes through cabinet seals. Minimized disturbance of the papers is realized by directing air onto the edges or ends of the papers. Both ascending and descending chromatography may be carried out with the cabinet hereof and separate normallyclosed solvent reservoirs are employed for each solvent tray disposed in the cabinet. The atmosphere within the cabinet is equilibrated so that contamination does not result and premature solvent evaporation is minimized.

Considering now one preferred embodiment of the invention in some detail, and referring to the accompanying drawings, the apparatus hereof includes a generally rectangular cabinet 11 having a hinged top 12 for access to the interior thereof. This top is preferably provided with a window 13 through which an operator may view the interior of the cabinet and also with a handle 14 for raising the top for access to the interior of the cabinet. Locking means 16 serve to tightly engage the top 12 with the lower portion of the cabinet 11 during chromatography processing. Upon the front of the cabinet 11 there is mounted a bank 17 of solvent reservoirs. This bank includes a plurality of separate reservoirs having individual caps 18 for filling of the separate reservoirs, and controllable piping means 19 extending from each reservoir into the inside of the cabinet 11 for the provision of solvent employed in the processing.

The preferred embodiment of the invention illustrated provides a cabinet structure formed of an inexpensive structural material, such as plywood, indicated by the numeral 21, and having an interior liner 22 formed of substantially imperivous material, preferably stainless steel. The reservoirs of the bank 17 are also formed of stainless steel and may be afiixed to the exterior of the cabinet adjacent the top thereof and in front of the cabinet, for ready access and utilization by one using the apparatus hereof. Each of the caps 18 upon the separate reservoirs is preferably spring-mounted, so as to normally remain in a closed position. The solvent 23 disposed within a reservoir may be fed into the cabinet through a flexible tube 24 extending from a stub pipe at the bottom of the reservoir, through a right angle into engagement with a fitting 26 through the front wall of the cabinet. A spout 27 extends into the cabinet from this fitting 26 for conduction of the solvent into the cabinet at a desired time, and also in a desired amount, if this control is required. This flow control means may comprise any of a variety of valving means such as, for example, the clamp 28 as illustrated in FIGURE 3. Although this flow control means 28 is illustrated in FIG- URE 3 as a screw clamp, it is only necessary for most applications of the invention to employ a means for pinching off the tube, which may be either manually or automatically operated to open and close the tube for flow of solvent.

Within the cabinet there are provided ledges upon which chromatography trays 31 are adapted to be mounted. These ledges are illustrated in FIGURE 3 as comprising right angle units 32, secured to the front and back walls of the cabinet with horizontal extensions for mounting of the chromatography trays. As regards these trays, same may be formed as elongated troughs 33, with end pieces 34 closing same. Both the trough and endpieces are preferably formed of stainless steel, so as to be impervious from attack by solvents that may be placed therein and also to have substantial durability and longevity, particularly as compared to glass units. Each of the trays 31 is provided with a pair of longitudinal bars 36, displaced above the trough 33 and extending through the end plates 34. These bars 36 are likewise preferably formed of stainless steel. The in dividual trays are substantially elongated and have a length somewhat less than the distance between the front and back walls of the cabinet 11, with the bars 36 extending from the end plates of the trays so as to rest upon the ledges 32 interiorly of the cabinet. This is best illustrated in FIGURE 3 wherein a single chromatography tray is shown in position within the cabinet. The solvent spout 27 extends through the front wall of the cabinet above the ledge 32, and is curved downwardly somewhat, as indicated, so that upon opening of the solvent conduit 24, solvent will flow from the spout 27 into the tray. It is from this tray that the solvent passes through the filter paper employed in chromatography processing to thereby wash the chemical mixture applied to the filter paper for sub-sequent analysis of same.

The top of the chromatography apparatus may also be formed of relatively inexpensive structural material, such as plywood. The top comprises an upper wall 41 and a lower wall 42 spaced apart as indicated, and connected by a vertical peripheral wall 43. The underside of the lower wall 42 is covered with a chemically impervious material, such as stainless steel, as indicated at 44, and a seal -46. formed of silicon rubber, or the like, is disposed entirely about the contact of the top 12 and the remainder of the cabinet 11. Consequently, upon closure of the top by pivoting of same about a rear hinge member 47, and latching of the top by the member 16, the entire interior of the cabinet is sealed in airtight relation to the atmosphere about the cabinet. In order to provide for direct viewing of the interior of the cabinet wherein chromatography processing is carried out, it is preferable to form the top portion of the cabinet as indicated in FIGURE 3, wherein the double section of the top does not extend to the front thereof, but instead, the upper wall 41 extends short of the front of the top, and the bottom wall 42 extends outwardly to the front of the cabinet with the window 13 therethrough engaging same in sealing relation. The handle 14 may be mounted also upon this forward extension of the lower Wall 42 of the top. It is noted at this point that the interior liner 44 provided upon the lower surface of the bottom wall 42 of the top also extends through an opening 48 therein, within which the window 13 is mounted, in order that all surfaces of the top normally communicating with the lower portion of the cabinet shall be fully protected against chemical attack from fumes and vapors from solvents employed therein.

As a further and highly important part of the top portion of the apparatus hereof,.there is provided an opening 51 through the bottom wall 42 of the top. This opening 51 is adapted to be closed by a movable plate 52. About the periphery of this plate there is disposed a sealing gasket 53 formed, for example, of silicon rubber so as to likewise be impervious to chemical attack. The plate itself is also preferably formed of stainless steel, or the like. This opening 51 in the top is provided for the purpose of accommodating air flow through the cabinet in order to dry filter paper disposed therein and employed in chromatography processing. An inlet duct 54 opens into a first chamber or passage 563 in the top between the upper and lower walls 41 and 42 thereof, with a suitable air filter 57 provided across this inlet opening. An exhaust duct 58 extends through the back peripheral wall 43 of the top for connection of a second top chamber or passage 56A to exhaust piping. Under the circumstances wherein an exhaust fan is provided in a chemical laboratory in which the apparatus hereof is employed, it is only necessary to attach an exhaust pipe 58 to the top. However, under alternative circumstances it may be desirable to actually connect an exhaust fan to the duct 58. Such connection is believed to be wholly within the skill of one versed in the art, so that no further description thereof is included herein.

The space between the upper and lower walls 41 and 42 of the top portion of the apparatus hereof is divided into two parts, 56A and 568, by a thick lateral wall 61 extending transversely across a part of the top within same, and across the top of the opening 51 in the bottom wall 42. Connected to one end of this thick transverse wall 61 is an additional wall 62, which extends rearwardly from an end of such wall into engagement with the rear wall 43 in the top. This is best indicated in FIGURE 2, wherein it will be seen that the transverse wall 61 extends from the left side of the top across the center of the opening 51 in the bottom wall 42 thereof, short of the right wall of the top, and there engages the wall 62 that extends to the back of the top. This wall 62 joins the back wall 43 of the top between the inlet and outlet ports 54 and 58. Both the walls 61 and 62 which form an airflow barrier in the top portion of the cabinet, extend into engagement with both the top and bottom walls 41 and 42 of the top of the cabinet, so that consequently suction of air from the port 58 will cause air to flow in the port 54 and thence around the wall 62 and through the opening 51 in the bottom wall of the top before entering the exhaust chamber 56A for removal by an exhaust fan connected to the port 58'.

With the plate 52 engaging the underside of the wall 42 in sealing relation, it will be seen that no amount of pumping upon the exhaust port 58 will draw air through the cabinet, for the exhaust passage 56A communicating with the port 58 is closed off within the top by closure of the movable plate 52. Only upon opening of this plate 52 by downward motion of same, as described below, is it possible for air to actually move through the top, and such air is then constrained to also move through the cabinet itself.

The present invention provides for remote control over positioning of the plate 52 either in closing relation to the cal shaft 71 which extends through an elongated bushing seal 72 mounted between the upper and lower walls 41 and 42 of the top through the thick lateral wall 61 thereof. The shaft 71 also extends through the plate 52 and a nut 73 is threaded upon the shaft beneath the plate 52 for urging an intermediate washer against the plate. Above the top wall 41 and exteriorly of the cabinet, there is mounted an elongated handle 74 which is pivotally secured to an upright bracket 76, in turn aflixed to this top wall 41. An angular projection 77 extends from the elongated handle 74 in rigid relation thereto, and is, in turn, pinned to the upper end of the shaft 71. A slot in the projection 77 at the pinned connection thereof allows vertical shaft motion with pivotal motion of the handle. It will thus be seen that rotational motion of the handle 74 serves to raise and lower the shaft 71, and consequently to raise and lower the plate 52 within the cabinet.

A spring lock mechanism 78 is provided for firmly holding the shaft 71 in any fixed position, and is shown as holding the plate 52 in closing relation to the opening 51 of the top. This spring lock mechanism may be quite conventionally formed in having a spring-loaded extension adapted to engage one or more V-notches in the shaft, and being released by a button, or the like, atop the latch mechanism. This latch mechanism 78 is mounted exteriorly of the cabinet upon the wall 41 of the top, and as above noted, serves to affix the shaft in a raised position, such as indicated by the solid lines in FIGURE 3.

The closure plate 52 is provided with means for insuring truly vertical motion of same in order to guarantee proper sealing of the gasket 53 about the edge thereof with the underliner 44 of the top. These means, also serving as an air flow baffle, include a pair of parallel upright walls 81 and 82, secured to the top of plate 52 and extending upwardly therefrom. The walls 81 and 82 are spaced apart a distance equal to the lateral width of the transverse wall 61 within the top. This wall 61 is preferably formed of an inexpensive structural material, such as wood, or the like, with smooth side surfaces that may be formed, for example, by the attachment of stainless steel thereto. In like manner, the upright walls 81 and 82 may also be formed of stainless steel. It will thus be seen that the plate 52 is fixed for sliding relation with the transverse wall 61 so as to be smoothly movable out of closing relation with the opening 51 in the wall 42, and into sealing relation with the wall for closure of this opening.

Movement of the plate 52 from a closed to an open position is relatively easily accomplished, merely by depression of the lock mechanism button, so as to retract the dog upon the mechanism 78 for releasing the shaft 71 for vertical motion. The handle 74 is then pivoted from the position shown in solid lines in FIGURE 3 to one such as shown in phantom therein. By such motion the shaft 71 is moved downwardly, and the plate 52 then follows same into the position shown in phantom in FIGURE 3. In any depressed or open position of the closure plate 52, passage is provided for air flow through the inlet port 54 in the top, and thence through the opening 51 therein down through the cabinet and back through the top and out the exhaust port 58 thereof. A material battling of air is afforded by the torturous passage provided in the top and also by the plate 52 which prevents direct air currents from impinging upon elements such as filter paper disposed within the lower portion of the cabinet. The plate walls 81 and 82 baflie air flow by preventing direct air flow between passages 56A and 56B when the plate is in open position so air must move about the plate and through the cabinet.

The chromatography cabinet 11 and top 12 may be formed of relatively inexpensive structural material, such as plywood, and the exterior coated or covered to present a pleasing and readily cleaned surface. Thus, for example, a Formica coating may be employed on the exterior of the cabinet and top. All surfaces of the apparatus normally exposed to the solvents or fumes thereof are formed of chemically impervious material to resist attack. Thus, the liner 22 covering the interior of the cabinet and the liner 44 covering the underside of the top may be formed of stainless steel. Also, all internal elements such as the movable plate 52, the trays 31, and ledges 32 are formed of or coated with stainless steel. The interior of the top 12 need not be protected to this extent, for solvent fumes and vapors passing therethrough are diluted by incoming air, and no extensive exposure of these surfaces to strong concentrations of solvents occurs.

Considering now the operation of the present invention and referring to the single preferred embodiment illustrated, the cabinet 11 is opened by undoing the latches 16 and pivoting the top 12 backwardly about the rear hinges 47. Individual trays 33 are disposed within the cabinet by resting the tray bars 36 upon the front and back ledges 32 within the cabinet. A filter paper, such as illustrated at 38 of FIGURE 4, is mounted upon each of the trays, and such may be accomplished by the utilization of a bar weight 39. The paper 38 is placed with one end inside of the tray and extends over one of the top side bars 36 with the bar weight 39 resting upon the paper in the tray. It will be appreciated that upon each of the filter papers 38 there is disposed some chemical mixture for analysis in acacordance with chromatography processing, and furthermore, that this unknown mixture is applied to the paper adjacent the top end thereof as same is mounted upon the tray. Chromatography solvent 23 is then placed within the individual reservoirs of the bank of reservoirs 17. A variety of different solvents are utilized in chromatography such as, fore example, phenol, acetic acid, propionic acid, ammonia, and isobutyric acid. In addition to the placement of the solvent in the reservoirs, it is also possible to place some of the solvent in the bottom of the cabinet, for reasons set forth below.

The cabinet is then closed by swinging the top 12 into the position illustrated in the drawings and latching the mechanism 16 to thereby seal the interior of the cabinet. The plate 52 is in raised position, as illustrated by solid lines in FIGURE 3, so that the interior of the cabinet is not only sealed from the atmosphere but also from any exhaust system connected to the top. Solvent is then introduced into the individual trays by operation of the flow controlling means 28 on the flexible tubes extending from the reservoirs into the cabinet. The invention provides for closed system chromatography. With the cabinet closed, the internal atmosphere is equilibrated so that chromatography proceeds in an atmosphere of the solvent. This may be furthered by placing additional solvent in the bottom of the cabinet and by heating the solvent, if desired. There results a volatilized solvent atmosphere in the box, and isolation of the chromatography paper and surrounding atmosphere in the box from the exterior of the box precludes contamination of the chromatography atmosphere. This is highly advantageous in obtaining optimized chromatography analysis, for there is excluded the possibility of atmospheric contaminants neutralizing or otherwise interfering with the action of the chromatography solvent. Thus, organic acid solvents as may -be employed in chromatography herein will not be inadvertently neutralized, for example, by the presence of vapors of bases in the surrounding atmosphere. The closed system also provides for limiting the evaporation rate of solvent from the paper during capillary solvent flow to permit a slower flow throughout the paper. By equilibrating the atmosphere, within which chromatography is carried out, the present invention then provides a material improvement in the possible precision of analysis and removes one of the undesirable variables normally encountered in chromatography.

The solvent within the chromatography tray 34 is drawn by capillary action'thr-ough the paper 38 held in the tray by the weight bar 39 resting upon the end of the 7 paper. There consequently results a movement or flow of solvent through the paper as is desired in chromatography. Particular note is made of the placement of the tray bars 36 above the top edges of the tray-s themselves. The paper 38 is extended over a bar 36, so as to leave an air gap along the paper above the tray. This is highly important in preventing siphoning of solvent from the tray. There is in effect formed a siphon air break preventing the formation of a liquid flow path about the solid tray surface. In the absence of this siphon air break, the wetted paper may form a siphon rapidly removing the solvent from the tray and passing the solvent through the paper at too rapid a rate for chromatography.

In accordance with conventional chromatography processing, the solvent flow is continued, at a very low rate for an extended period of time until a predetermined or observed solvent dispersion of the chemical unknown has been obtained. At this point in the processing, it is desired to dry the chromatography paper in order that conventional analytical methods may be employed. to identify the constituents of the unknown operated upon. The present invention, in distinction to prior art chromatog raphy processing, provides for the drying of the paper without exposure of same to the external atmosphere. Not only is the difficulty of handling wet chromatography paper overcome hereby, but also the highly deleterious effects of solvents fumes and vapors are precluded from annoying or injuring operators.

In order to dry the paper within the cabinet 11, the handle 74 atop the cabinet is pivoted upwardly toward the position illustrated in phantom in FIGURE 3. The spring latch mechanism 78 is first released by pressing the button on the top thereof to withdraw the dog engaging the notch in the vertical shaft 72, and then the handle 74 is pivoted upwardly to thereby depress the shaft 71. The closure plate 52 carried by the shaft 71 is then moved downwardly toward the position illustrated in phantom in FIGURE 3, so as to uncover the opening 51 in the lower Wall 42 of the top. As the plate 52 moves downwardly, the upstanding walls 81 and 82 thereon slide down along the central wall 61 of the top. Connection of the exhaust duct 58 to exhaust means then produces a suction through the cabinet enclosure from the inlet port 54 in the top. Air flow enters this port 54 through the air filter 57 and is directed through passage 56B down through one side of the opening 51 and about the plate 52 to thereby replace the solvent atmosphere in the cabinet. Air and gas are withdrawn from the cabinet about the plate 52 through the other side of the opening 51 and the exhaust passage 56A to the exhaust port 58 and exhaust means. There may be connected to the exhaust port 58 either an extension of a conventional exhaust system normally provided in chemical laboratories or a separate exhaust fan preferably exhausting to some relatively inaccessible area whereat the fumes and vapors from the cabinet will be dispersed before inhalation by human beings.

It will be seen from the foregoing, that the structure of the cabinet top and closure plate 52 thereon prevents the establishment of direct air flow paths or air currents within the cabinet, such as might cause a fluttering of the papers therein and possible contact between adjacent papers. The entire drying process of the chromatography paper is carried out within the cabinet, and all fumes and vapors within the cabinet are exhausted therefrom before the cabinet top is unlatched and opened. Consequently, one operating the apparatus hereof is at no time exposed to fumes and vapors of the solvents employed in chromatography. It is further noted that any solvent remaining in the trays at the termination of a run must be evaporated therefrom for drying of the sheets. This invention provides for top air entry so as to maximize evaporation at the upper end of the sheets and thus to remove excess solvent and stop the chromatography as evenly as possible.

It will, of course, be appreciated that ascending chromatography may also be carried. out with the apparatus hereof. In such case, the solvent is provided in the bottom of the cabinet and the chromatography papers are mounted to depend into this pool of solvent at the bottom of the cabinet. In this latter instance, it is possible to provide individual chromatography trays at the bottom of the cabinet with mounting bars for the chromatography paper adjacent the top of the cabinet. Particular attention is invited to the fact that the total absence of fumes and vapors in the cabinet, at such time as it is opened, allows an operator to place items such as trays or the like at the bottom of the cabinet even though it might be necessary for such operator to then directly breath air within the cabinet. All odoriferous and injurious fumes and vapors are removed from the cabinet so that the operator experiences no difficulty or discomfiture in reaching into the cabinet or in placing his head in close proximity with the open cabinet top.

Following processing as set forth above, chromatography papers are then removed from the cabinet and separately analyzed. in conventional manners to determine the constituents of chemical mixtures which have been applied to the filter papers. There is provided by the present invention means for combining the solvent flow operation and drying operation of chromatography in one closed system, so that the operator is at no time exposed to the solvents employed in chromatography. Only dry paper is removed from the cabinet, so that there is also achieved a material saving in time, a minimization of handling, and an elimination of many sources of errors and. difficulties otherwise encountered in chromatography. Equilibration of the atmosphere in which solvent flow is carried out, in itself provides a material improvement in chromatography, and the closed system of the present invention provides for this equilibrium.

There has been described above a single preferred embodiment of the present invention, however it is not intended to limit the invention by the precise terms of this description and, instead, reference is made to the appended claims for a precise delineation of the true scope of this invention.

What is clamed is:

1. Chromatography apparatus comprising a cabinet containing chromatography sheets therein, a plurality of solvent reservoirs carried by said cabinet, a plurality of removable trays removably mounted in said cabinet, means controllably connecting reservoirs and trays for metering solvent into the trays, a top having a pair of passages therethrough and movably mounted upon said cabinet for sealing the interior thereof, an inlet duct and an outlet duct connected to each of said passages of said top respectively for air flow, said top having an opening through the underside thereof communicating with both top passages, and a movable plate mounted for remote positioning into and out of sealing relation with said top about the opening through the underside thereof for controllably opening the cabinet interior to air flow.

2. Chromatography apparatus comprising a cabinet defining a sealed chamber containing chromatography sheets therein for chromatography and having a pivotallymounted closure for sealing the cabinet interior, said closure including separated air inlet and air exhaust passages and having an opening from both passages to the interior of the cabinet, a plate slidably mounted within said cabinet for movement into and out of sealing relation to said opening, and means exteriorly of said cabinet for moving said plate to seal the cabinet interior during chromatography solvent movement and to open the cabinet interior to air flow for drying chromatography sheets therein.

3. Chromatography apparatus as set forth in claim 2 further defined by a wall extending across said opening, said plate having a pair of thin walls slidably engaging said wall on opposite sides thereof to form an air baffle When said plate is out of sealing relation to said opening for directing air over the plate and through the cabinet to accomplish bafiled air flow through the cabinet.

4. Chromatography apparatus for separation by solvents of materials upon chromatography sheets comprising a cabinet having an open top, said cabinet having chromatography sheets therein, said cabinet having a chemically impervious lining and a substantial depth from said open top, said cabinet having means therein to hold solvent and to mount chromatography sheets, means introducing solvent into said cabinet for chromatography, a top member pivotally engaging said cabinet and having separated top and bottom Walls, means sealing said top member to said cabinet for confining solvent fumes and the like within the cabinet, said top member having an opening through the bottom thereof and an interior wall extending across said opening for dividing the top member into two separate chambers, a plate mounted beneath said opening for remotely controlled reciprocal motion into and out of closed relation to said opening, said plate having at least one upright wall slidably engaging the wall of said top member across the opening whereby said upright wall separates said top chambers, and means defining an inlet port and an exhaust port in said top member communicating with each of said chambers respectively for exhaust circulation of air through the cabinet when the top member is closed and the plate is out of closed relation to said top opening and for removing fumes and the like from the cabinet and for drying chromatography sheets.

5. Chromatography apparatus as set forth in claim 4 further defined by a vertical shaft reciprocally mounted in the top member and extending beyond both top and bottom walls, said shaft extending through said plate and having means threaded upon its lower end for adjustably securing the plate to the shaft, a lever handle pivotally mounted upon the top wall of said top and engaging said shaft for controlled reciprocation of said shaft from without the cabinet with the top closed thereon, and releasable spring latch means engaging said shaft atop said top for releasably holding the shaft in upwardly reciprocated position for maintaining the plate in closed relation to said opening in the top during solvent movement in chromatography sheets within the cabinet.

6. Apparatus for chromatography in which a solvent slowly moves along a chromatography sheet to separate chemicals thereon comprising a box having an open top and lined with a chemically inert liner, said box having chomatography sheets therein, a ledge along opposite interior sides of said box, a plurality of thin elongated chromatography trays removably supported upon said ledges, a solvent reservoir afifixed to said box exteriorly thereof and having tubes extending into the box with spouts therein directed toward respective trays for filling the trays after the box has been closed, a top member pivotally mounted upon the box for closure into sealing relation with the box, latch means for securing said top member in closed position, said top member defining inlet and exhaust passages terminating at a common opening into the interior of said box, a wall separating said passages at said opening, a sealing plate depending from said top member beneath said opening and having a bafiie extending upwardly from said plate adjacent and aligned with said wall, and means operable from above said top member for mounting said plate for reciprocation to move the same into and out of closing rela tion with said opening where-by closure of said plate seals the box interior for chromatographic chemical separation within the box and opening of said plate provides a bafded air flow path through said box interior for evaporating solvent from the box without escape to the atmosphere of solvent fumes and vapors.

7. Apparatus for chromatography in which a solvent moving through a sheet separates chemicals thereon for analysis comprising a deep cabinet having an open top and stainless steel liner, said cabinet having chromatography sheets therein, a closure member hinged upon the top of said cabinet for sealing the interior of the cabinet and having a stainless steel under surface, said closure member defining a pair of passages therethrough extending from inlet and exhaust ports at the hinged side of the member to adjacent openings through the bottom of the member, a plate disposed beneath said closure member, means mounting said plate for reciprocation from the top of said closure member for moving the plate into and out of closing relation to the adjacent openings in the member, at least one solvent reservoir affixed to said cabinet with an opening to the exterior of the cabinet and a drain to the interior of the cabinet for metering solvent into the cabinet, and a plurality of means for mounting said chromatography sheets within the cabinet whereby an entire chromatography process including drying may be accomplished in the cabinet sealed from the atmosphere.

References Cited by the Examiner UNITED STATES PATENTS 234,879 11/1880 Macurdy 90 X 621,689 3/1899 Meier et al. 22025 745,558 12/1903 Ba-rtol 9590 750,665 1/1904 Lesper-ance 95-90 751,552 2/1904 Plumely 9590 978,590 12/1910 Hutton 95-90 2,017,728 10/1935 Oakamp 34-225 X 2,370,422 2/ 1945 Reed 34231 X 2,708,519 5/ 1955 Novak 210269 2,801,024 7/1957 Osborne 22063 2,986,280 5/1961 Magnuson et al. 210-198 FOREIGN PATENTS 105,175 4/1917 Great Britain.

OTHER REFERENCES Block et al.: Paper Chromatography and Paper Electrophoresis, Second edition (1958), Academic Press Inc. New York, pages 24, 27, and 63.

REUBEN FRIEDMAN, Primary Examiner. 

1. CHROMATOGRAPHY APPARATUS COMPRISING A CABINET CONTAINING CHROMATOGRAPHY SHEETS THEREIN, A PLURALITY OF SOLVENT RESERVOIRS CARRIED BY SAID CABINET, A PLURALITY OF REMOVABLE TRAYS REMOVABLY MOUNTED IN SAID CABINET, MEANS CONTROLLABLY CONNECTING RESERVOIRS AND TRAYS FOR METERING SOLVENT INTO THE TRAYS, A TOP HAVING A PAIR OF PASSAGES THERETHROUGH AND MOVABLY MOUNTED UPON SAID CABINET FOR SEALING THE INTERIOR THEREOF, AN INLET DUCT AND AN OUTLET DUCT CONNECTED TO EACH OF SAID PASSAGES OF SAID TOP RESPECTIVELY FOR AIR FLOW, SAID TOP HAVING AN OPENING THROUGH THE UNDERSIDE THEREOF COMMUNICATING WITH BOTH TOP PASSAGES, AND A MOVABLE PLATE MOUNTED FOR REMOTE 